Power feeding coil unit and wireless power transmission device

Abstract

A power feeding coil unit includes a power feeding coil, and an auxiliary coil. The auxiliary coil is arranged not to interlink with a magnetic flux that interlinks with a power receiving coil that is arranged to face the power feeding coil during power feeding. An axial direction of the auxiliary coil is nonparallel to an opposing direction of the power feeding coil and the power receiving coil. A direction of circulation of a magnetic flux generated by the auxiliary coil is opposite to a direction of circulation of a magnetic flux generated by the power feeding coil.

What is claimed is: 
     
       1. A power feeding coil unit for wireles sly feeding power, comprising:
 a power feeding coil; and 
 an auxiliary coil, wherein 
 the auxiliary coil is arranged not to interlink with a magnetic flux that interlinks with a power receiving coil that is arranged to face the power feeding coil during power feeding, 
 an axial direction of the auxiliary coil is nonparallel to an opposing direction of the power feeding coil and the power receiving coil, 
 a direction of circulation of a magnetic flux generated by the auxiliary coil is opposite to a direction of circulation of a magnetic flux generated by the power feeding coil, 
 the power feeding coil comprises a first power feeding coil and a second power feeding coil that are apposed, and 
 a magnetic path interlinking the first power feeding coil and the second power feeding coil is generated by a magnetic field of the first power feeding coil and a magnetic field of the second power feeding coil. 
 
     
     
       2. The power feeding coil unit according to  claim 1 , wherein
 the magnetic flux generated by the auxiliary coil does not cancel a magnetic flux that is generated by the power feeding coil and is interlinking with the power receiving coil, and the magnetic flux generated by the auxiliary coil cancels some amount of magnetic flux that is generated by the power feeding coil and is not interlinking with the power receiving coil. 
 
     
     
       3. The power feeding coil unit according to  claim 1 , wherein
 a magnetic field generated by the auxiliary coil enhances a part of a magnetic field between the power feeding coil and the power receiving coil. 
 
     
     
       4. The power feeding coil unit according to  claim 1 , wherein
 each of the power feeding coil and the auxiliary coil includes a magnetic core, and 
 the magnetic core of the auxiliary coil is coupled to the magnetic core of the power feeding coil. 
 
     
     
       5. The power feeding coil unit according to  claim 1 , wherein
 the auxiliary coil is located on the opposite to a side of the power feeding coil facing the power receiving coil. 
 
     
     
       6. The power feeding coil unit according to  claim 5 , wherein
 the auxiliary coil is arranged so that part or all of the auxiliary coil overlaps the power feeding coil when viewed from the opposing direction of the power feeding coil and the power receiving coil. 
 
     
     
       7. The power feeding coil unit according to  claim 1 , wherein
 an axis of the auxiliary coil is substantially perpendicular to the opposing direction of the power feeding coil and the power receiving coil. 
 
     
     
       8. The power feeding coil unit according to  claim 1 , wherein
 at least part of the magnetic flux generated by the auxiliary coil interlinks with the power feeding coil. 
 
     
     
       9. The power feeding coil unit according to  claim 1 , wherein
 the auxiliary coil comprises a first auxiliary coil and a second auxiliary coil, and 
 the first auxiliary coil and the second auxiliary coil are arranged so that a center portion of the power feeding coil is located between a center portion of the first auxiliary coil and a center portion of the second auxiliary coil.